Battle plan for Entity Controllers and the developer interface

During DrupalCamp Berlin fago, sun and fubhy (me) actively discussed the entity concept and especially the entity controller concept.

The topics we talked about

  1. How to split up the current EntityController into separate, more specialized controllers (storage, cache, etc.).
  2. How to combine functionality of separated controllers in cases where two or more controllers need to collaborate (e.g. storage and caching).
  3. How to design the structure of hook_entity_info() to support multiple controllers.